Lambda | Chinese Rule of Eight

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

int [] fibNum = { 1, 1, 2, 3, 5, 8, 13, 21, 34 };

//num => num % 2 == 1, means get any number with modulo of 1 (AKA odd number)

//in our case, its 1, 1, 3, 5, 13, 21.

//Average() means add all of these numbers up and divide by how many there are

// 1+1+3+5+13+21/6 = 7.333333

double averageValue = fibNum.Where(num => num % 2 == 1).Average();

Console.WriteLine(averageValue);

Search for string in string array

lambda

string [] arr1 = new string[] { "otwone", "two", "threetwo", "fotwour", "five", "two" };

foreach (string s in arr1.Where(

x => {

if(x.Contains("two")) {

return true;

}

return false;

}

)) Console.WriteLine(s);

Result:

otwone
two
threetwo
fotwour
two

LinQ

string [] arr1 = new string[] { "otwone", "two", "threetwo", "fotwour", "five", "two" };

var query = from arr in arr1

where arr.Contains("two")

select arr;

foreach(var s in query) {

Console.WriteLine("{0}", s);

}

Result:

otwone
two
threetwo
fotwour
two

Determine if any ints are larger or less

Lambda

int[] source = new[] { 3, 8, 4, 6, 1, 7, 9, 2, 4, 8 };

foreach (int i in source.Where(

x => {

if (x <= 3) {

Console.WriteLine("less than or equal to 3: {0}",x);

return true;

}

else if (x >= 7) {

Console.WriteLine("more than or equal to 7: {0}",x);

return true;

}

return false;

}

)) Console.WriteLine(i);

Result:

less than or equal to 3: 3
3
more than or equal to 7: 8
8
less than or equal to 3: 1
1
more than or equal to 7: 7
7
more than or equal to 7: 9
9
less than or equal to 3: 2
2
more than or equal to 7: 8
8

Find age in Array of Structs

linQ

public class Program

{

struct Item

{

public int a;

public string b;

public Item(int a, string b)

{

this.a = a;

this.b = b;

}

};

public static void Main() {

Item [] people = {

new Item( 12, "little todd" ),

new Item( 13, "little timmy" ),

new Item( 36, "Ricky"),

new Item( 33, "zelda")

};

var oldQuery = from person in people

where (person.a >= 30)

select person;

foreach(var s in oldQuery) {

Console.WriteLine("old person {0}", s.b);

}